Woven fourdrinier fabric

ABSTRACT

A woven Fourdrinier fabric so constructed that it has a relatively long useful life. The fabric is characterized by having at least two interconnected plies with each ply being of a mesh weave and wherein the size and number of yarns per square inch thereof are such that each ply has at least about 9% open area for permitting drainage therethrough of liquid from a slurry used in the manufacture of paper and the like.

United States Patent [1 1 Slaughter [451 May 27, 1975 WOVEN FOURDRINIERFABRIC [75] Inventor: Philip H. Slaughter, Charlotte, NC.

[73] Assignees: Evans S. Creech; Jimmie O.

Hutchins; John W. Whitley, all of Charlotte, NC. part interest to each[22] Filed: Nov. 21, 1973 [21] Appl. N0.: 417,873

[52] US. Cl. 139/425 A; 162/DIG. l [51] Int. Cl. D03d 15/00; D03d 15/02;D2lf 1/10 [58] .Field of Search 139/425 A, 425 R, 420 R, 139/383 A,408-415; 162/348, 349, DIG. 1; 74/239; 34/95; 245/2, 8; 102/348, 349,DIG.

[56] References Cited UNITED STATES PATENTS 2,157,082 5/1939 Milnes139/383 A 2,903,021 9/1959 Holden et a1. 139/383 A 2,934,097 4/1960I-Iindle et a1. 139/383 A 2,936,796 5/1960 I-Iindle et al. 139/383 A2,949,134 8/1960 Hindle et al. 139/383 A 3,127,308 3/1964 Justus et a1.139/425 A 3,207,659 9/1965 Wagner 162/348 X 3,222,246 12/1965 Lee162/349 3,322,617 5/1967 Osborne 162/349 X 3,325,909 6/1967 Clark 74/2393,473,576 10/1969 Amneus 139/425 A 3,573,164 3/1971 Friedberg et a1.139/425 A FOREIGN PATENTS OR APPLICATIONS 22,813 3/1962 Germany l62/DIG.1 47-44,444 11/1972 Japan 162/DIG. 1

297,738 4/1971 U.S.S.R l62/DIG. 1

Primary ExaminerJames Kee Chi Attorney, Agent, or Firm-Parrott, Bell,Seltzer, Park & Gibson [5 7] ABSTRACT A woven Fourdrinier fabric s0constructedthat it has a relatively long useful life. The fabric ischaracterized by having at least two interconnected plies with each plybeing of a mesh weave and wherein the size and number of yarns persquare inch thereof are such that each ply has at least about 9% openarea for permitting drainage therethrough of liquid from a slurry usedin the manufacture of paper and the like.

8 Claims, 4 Drawing Figures WOVEN F OURDRINIER FABRIC This inventionrelates to an improved fabric for use in the construction of endlessFourdrinier forming belts employed in the manufacture of paperandcomparable fibrous materials.

It is well known in the papermaking industry that paper is produced byflowing a slurry of pulp or cellulosic fibers and/or other papercomponents mixed with water and/or other liquid onto a moving'endlessbelt commonly known as a Fourdrinier forming belt. Fourdrinier formingbelts are necessarily of substantial length and are quite porous so thata major portion of the liquid is removed from the slurry by drainage.After most of the liquid has been removed, the thus formed paper web istransferred to a so-called papermakers drier felt which conveys thepaper web through the nips of heated cylinders to extract the residualmoisture from the paper web.

Papermakers drier felts are generally formed of a very coarse, compactlywoven fabric, and the capillary potential of such fabric is relied uponto aid in the removal of moisture from a paper web product beingprocessed thereon. Papermakers drier felts necessarily have no more thanabout 2 percent to 3 percent open area throughout the same in order toserve their intended function of supporting and conveying the paper webduring the extraction of residual moisture therefrom. Fourdrinierforming belts, on the other hand, are quite distinct from drier felts inthat at least the face thereof must be of a fine mesh weave with themesh thereof being of such size and count as to readily permit drainageof liquid from the slurry, while providing a satisfactory supportingsurface for obtaining a paper product of the desired quality.Fourdrinier belts may be woven from metallic, natural and/or syntheticwarp and weft yarns or strands, and it is necessary that such belts areof high tensile strength so as to be placed under substantial tension.

Fourdrinier forming belts also must be highly stable; i.e., it is highlydesirable that such belts will be subject to very little, if any,stretch or elongation and/or contraction in normal use so that thestrands or yarns thereof will not shift excessively relative to eachother and thereby unduly restrict, close or elongate the openings orinterstices in the belt. However, Fourdrinier forming belts have been ofsingle ply woven construction heretofore, and have thus been soconstructed as to have an undesirable relatively short usefullife-because of the flexing, relatively rapid abrasion and consequentfracture of the surfaces of those portions of the strands of the beltwhich engage and necessarily creep or slide on the supporting rolls andother supporting surfaces of a papermaking machine. Such portions of thestrands in a Fourdrinier forming belt are generally known as warpknuckles and/or shute knuckles. Since Fourdrinier forming beltsgenerally have an overall length of up to about 140 feet, not only arethey quite expensive to manufacture, but considerable expense anddowntime are involved in replacing an excessively worn or fracturedFourdrinier forming belt with a new one.

It is therefore an object of this invention to provide an improvedFourdrinier forming belt fabric of high dimensional stability and whichis so constructed as to have a life in normal use substantially greaterthan that of any Fourdrinier forming belts known heretofore.

It is a more specific object of this invention to provide an endlessFourdrinier forming belt fabric comprising at least two interconnectedlayers or plies of woven mesh fabric, namely, an outer or top ply and aninner or bottom ply, and wherein the size and number of warp yarns andweft yarns per square inch of the fabric are such that each ply thereofhas at least about 9 percent open area therethrough, at least in themajor or formation area of the fabric; i.e., the area upon which theslurry is deposited, so that liquid from the slurry, when received onthe top ply of the fabric, may readily drain through the fabric, and thebottom ply thus serves as a wearing surface which may be substantiallyworn away before the top ply is subjected to abrasion by contact withthe supporting rolls of a papermaking machine, thereby greatly extendingthe useful life of the Fourdrinier forming belt fabric.

It is another object of this invention to provide a Fourdrinier formingbelt fabric of the type described wherein the warp and weft yarnsthereof are of synthetic material.

Some of the objects and advantages of the invention having been stated,others will appear as the description proceeds when taken in connectionwith the accompanying drawings, in which FIG. 1 is a partially explodedschematic perspective view of the improved endless Fourdrinier formingbelt fabric of this invention;

FIG. 2 is a schematic transverse or warpwise sectional view through aportion of the improved Fourdrinier fabric taken substantially alongline 22 in FIG.

FIG. 3 is a fragmentary weftwise sectional view taken substantiallyalong line 33 in FIG. 2; and

FIG. 4 is an enlarged fragmentary top plan view of a portion of thefabric illustrating the mesh construction thereof.

Referring more specificially to the drawings, the preferred embodimentof the improved Fourdrinier forming belt fabric of the present inventionis broadly designated at 10 and comprises an outer or face ply or layer11 and an inner or backing ply or layer 12 which are arranged insuperposed relationship, and both of which are preferably of endlessform. The outer and inner plies 11, 12 also may be termed as respectivetop and bottom plies of the belt fabric, since the plies 11, 12 occupysuch pbsition when in use and when passing through the slurry-receivingupper reach of the Fourdrinier forming belt formed thereof.

At least the top or outer ply 11 should be of a relatively'fine meshweave and, in any event, both of the plies 11, 12 should be of a meshweave having at least 9 percent open area throughout the same, as bestshown in FIG. 4, so as to readily permit drainage therethrough of liquidfrom a slurry used in the manufacture of paper and the like. The outeror top ply is woven of main warp yarns 13 and weft yarns 14, and theinner or bottom ply 12 is woven of main warp yarns l5 and weft yarns 16.Although each of the plies 11, 12 is shown as being in the form of aplain weave, in is to be understood that they may be of any othersuitable weave constructions, such as a twill or semi-twill weave, forexample.

The outer and inner plies 11, 12 of the Fourdrinier fabric 10 arepractically independent of {each other. However, the plies 11, 12 areinterconnected by a plurality of interlacing binder warp yarns 17 whichextend generally parallel with the main warp yarns 13, 15, and whichextend transversely across the Fourdrinier belt fabric (FIG. 1). It ispreferred that there are at least twice as many main warp yarns l3, ineach respective layer of the fabric 10 as there are binder warp yarns17. Also, it is preferred that the binder warp yarns 17 are spacedweftwise apart from each other as shown in FIGS. 3 and 4, for example,so that the outer and inner plies 11, 12 may shift or yield relative toeach other when the Fourdrinier belt fabric 10 is in use and assuccessive portions of the belt fabric are moving in engagement with thecylindrical surfaces of supporting rolls of a papermaking machine,thereby reducing the abrasive action to which the inner or bottom ply 12may be subjected by frictional engagement with such surfaces.

As shown in FIGS. 2 and 3, the plies 11, 12 are spaced apart forpurposes of clarity. However, it is to be understood that the two pliesactually are held in contact with each other by the binder warp yarns17. As indicated above, it is preferred that there is a lesser number ofbinder warp yarns 17 in the Fourdrinier forming belt fabric 10 thanthere are warp yarns in each ply 11, 12 thereof. As shown in FIGS. 3 and4, there is one binder warp yarn for every seven main warp yarns in eachply, for example. Also, binder warp yarns 17 may be somewhat smallerthan at least the warp and weft yarns 13, 14 of the outer or face ply11, if desired. As preferred, the binder warp yarns 17 are looped overalternate weft yarns 14 in outer ply 11 and they are looped beneathintervening weft yarns 16 in inner ply 12 of fabric 10.

When the Fourdrinier belt fabric 10 is woven in endless form, as shownin FIG; 1, it is to be noted that the weft yarns 14, 16 in the two plies11, 12 are continuous and extend longitudinally throughout the upper andlower reaches of the Fourdrinier forming belt fabric and, since the beltfabric 10 is woven in a progressive manner, the weft yarns 14, 16 extendin generally helical form progressing from one edge of the fabric to theother. Of course, the warp yarns l3, 15, 17 of the endless Fourdrinierforming belt fabric extend transversely or across the belt fabric.

It is preferred that the Fourdrinier forming belt fabric 10 of thisinvention is woven from multifilament synthetic yarns, although it is tobe understood that the yarns may be in the form of metal strands, theymay be in the form of metal strands coated with a plastic material, theymay be in the form of continuous multifilaments or monofilaments, theymay be formed from yarns of natural or man-made staple fibers or theymay be of any suitable combination of filaments and/or fibers ofdifferent types. In the event that metal or plastic-coated metal yarnsare present in the belt fabric 10, it is preferred that the top ply 11thereof is woven of synthetic continuous-filament or staple-fiber yarns,since synthetic yarns are generally less brittle than metal yarns, andsynthetic yarns generally provide a more durable and smoother surfacefor receiving a slurry of pulp and water thereon than is the case withrespect to metal yarns.

If plastic coated metal yarns are employed in weaving the fabric 10, itis preferred that they are used to extend in only the widthwisedirection of the Fourdrinier belt formed therefrom and with yarns ofmore pliable synthetic and/or natural textile material extending in thelengthwise direction of the belt. By such an arrangement of the plasticcoated metal yarns, they would be subjected to relatively little or noflexing as they passed about rolls and over the edges of suction boxtops of a Fourdrinier forming machine.

Further, if synthetic yarns are used, it is preferred that the wovenendless belt fabric is heat-set to aid in preventing stretching of thebelt, and it is preferred that the yarns are of the continuous filamenttype since they would normally be of greater tensile strength thanstaple-fiber synthetic yarns. Typical synthetic yarns which may be usedin the maufacture of the belt fabric may be formed from nylon,polyester, acrylic, polypropylene or other synthetic strand materials.As shown, all of the main warp yarns 13, 15 and the weft yarns 14-16 areabout the same size. It is apparent, however, that many different sizesand types of yarns may be used in forming the fabric 10 in accordancewith this invention.

Since, in the preferred embodiment, the weft yarns 14, 16 extendlengthwise of the Fourdrinier belt fabric and are endless to the extentthat each weft yarn extends around the belt fabric 10 in a generallyhelical configuration, it will be noted that the weft yarns 14, 16 aresubstantially straight, thereby further contributing to the lengthwisedimensional stability of the endless Fourdrinier belt fabric. The warpyarns 13, 15, on the other hand, curve over, between and under the weftyarns. Thus, the warp yarns 13, 15 are formed with knuckles where theyloop over and under the respective weft yarns 14, 16, which knucklesconstitute the wearing surfaces of the Fourdrinier fabric.

It is thus seen that I have provided an improved multi-ply Fourdrinierforming belt fabric which is especially constructed to withstandflexing, high tension and abrasion incidental to paper manufacture,thereby enhancing the useful life of the fabric. It is seen further thatthe fabric comprises at least two interconnected plies, each of which isformed of respective interwoven warp and weft yarns with theinterconnected plies being endless and including at least a top or faceply and a bottom or backing ply. The fabric plies are woven in a finemesh with at least 9 percent of the area thereof being open with theopenings or interstices therein being of substantially the same size andsubstantially uniformly distributed throughout the fabric 10. In otherwords, at least about 9 percent of the area of each ply throughout thefabric is devoid of any yarns to accommodate the free flow of drainingliquid therethrough generally perpendicular thereof.

The 9% open area through the belt fabric 10 generally is suitable toaccommodate a slurry of pulp and water containing relatively short andfine fibers during the formation of a sheet of paper or the likethereon. In instances where the fibers of the slurry are appreciablylonger, it is apparent that a more open mesh weave may be employed. Inany event, the open area of each ply should be such as to permit a rateof drainage of the liquid therethrough facilitating the formation of asheet of paper of the desired quality upon the outer or face surface ofthe Fourdrinier forming belt fabric.

As indicated earlier herein, when the belt fabric is in use, the innerply 12 thereof is subjected to the larger portion of the wear of thecomposite fabric, thereby generally protecting the warp and weft yarns13, 14--of the face ply from frictional wear, since a substantiallygreater portion of the frictional wear occurs on the back or inner sideof a Fourdrinier forming'b elt fabric than that occurring on the face orouter side thereof;

e.g.. the inner ply may creep in frictional engagement with the variousrolls and may slide over and against foils, suction box tops and othersupporting surfaces of a Fourdrinier forming machine. Also, it isapparent that the inner ply 12 not only reinforces the top or outer ply11, but it also enhances the dimensional stability of the Fourdrinierforming belt fabric. The stability of the Fourdrinier fabric may befurther enhanced by bonding the two plies ll, 12 together at suitablyspaced areas, if desired. Such bonding may be effected by use of asuitable adhesive and/or by heat fusion of the plies together at suchspaced areas.

It is preferred that the fabric 10 is woven in endless form, asdescribed herein, so that the weft yarns thereof will extend lengthwisearound the Fourdrinier belt formed therefrom. It is apparent, however,that the fabric may be woven of the desired weftwise width and inindefinite warpwise lengths, after which the fabric may be cut to thedesired warpwise lengths and opposite ends thereof then may be suitablyspliced together to form an endless Fourdrinier belt therefrom.

in the drawings and specification there has been set forth a preferredembodiment of the invention and, although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation.

That which is claimed is:

l. A Fourdrinier fabric comprising at least two woven plies ofrespective sets of weft yarns and warp yarns, binder warp yarnsinterwoven with and interconnecting said two plies, and each of saidplies being in the form of a mesh weave having an open area of at leastabout 9% per square inch thereof.

2. A Fourdrinier fabric according to claim 1, wherein both of said pliesare endless with one ply surrounding the other ply.

3. A Fourdrinier fabric according to claim 1, wherein one of said pliesis an outer ply and the other of said plies is an inner ply, the warpyarns of each ply extending transversely across the width of the fabric,and the weft yarns in each ply extending lengthwise and around thefabric so that each ply is of substantially endless form with the weftyarns in said outer ply encircling said inner ply.

4. A Fourdrinier fabric according to claim 1, wherein the warp yarns inthe two plies are approximately the same size.

5. A Fourdrinier fabric according to claim 1, wherein said weft yarnsand said warp yarns in the two plies are synthetic yarns.

6. A Fourdrinier fabric according to claim 1, wherein said binder warpyarns are substantially smaller than said warp yarns in the two plies.

7. A Fourdrinier endless belt fabric comprising a pair of superposedouter and inner endless woven plies of respective sets of weft yarns andmain warp yarns, binder warp yarns interwoven with an interconnectingsaid outer and inner endless woven plies, the warp yarns of each plyextending transversely across the endless belt fabric, the weft yarns ineach ply extending lengthwise thereof and around the belt fabric insubstantially endless form, all of the yarns being multifilamentsynthetic yarns, and each of the plies being a mesh weave havinginterstices therethrough forming an open area of at least about 9% persquare inch of each ply with the interstices of each ply beingsubstantially uniformly distributed throughout the respective ply forpermitting liquid to drain through the Fourdrinier belt fabric.

8. A Fourdrinier fabric comprising at least two woven plies ofrespective sets of weft yarns and warp yarns, binder yarns interwovenwith an interconnecting said two plies, and each of said plies being inthe form of a mesh weave having an open area of at least about 9% persquare inch thereof.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3, 885,602

DATED May 27, 1975 INVENTOR(S) 1 Philip H. Slaughter It is certifiedthat error appears in the above-identified patent and that said LettersPatent Q are hereby corrected as shown below:

Column 6, CLAIM 7, Line 19, "an" should be --and-- Signed and Sealedthis 0 twenty-sixth Day Of August 1975 [SEAL] Arrest:

O RUTH c. MASON c. MARSHALL DANN Arresting Officer Commissioneruj'lalenls and Trademarks 3,885,602 Dated May 27, 1975 Philip H.Slaughter Patent No.

Inventor(s) It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 34 "an" should be and Signed and Sealed this sixteenth Day Of September 1 975 {SEAL} v A ttest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (mnmissiuner nj'Patentsand Trademarks

1. A Fourdrinier fabric comprising at least two woven plies ofrespective sets of weft yarns and warp yarns, binder warp yarnsinterwoven with and interconnecting said two plies, and each of saidplies being in the form of a mesh weave having an open area of at leastabout 9% per square inch thereof.
 2. A Fourdrinier fabric according toclaim 1, wherein both of said plies are endless with one ply surroundingthe other ply.
 3. A Fourdrinier fabric according to claim 1, wherein oneof said plies is an outer ply and the other of said plies is an innerply, the warp yarns of each ply extending transversely across the widthof the fabric, and the weft yarns in each ply extending lengthwise andaround the fabric so that each ply is of substantially endless form withthe weft yarns in said outer ply encircling said inner ply.
 4. AFourdrinier fabric according to claim 1, wherein the warp yarns in thetwo plies are approximately the same size.
 5. A Fourdrinier fabricaccording to claim 1, wherein said weft yarns and said warp yarns in thetwo plies are synthetic yarns.
 6. A Fourdrinier fabric according toclaim 1, wherein said binder warp yarns are substantially smaller thansaid warp yarns in the two plies.
 7. A Fourdrinier endless belt fabriccomprising a pair of superposed outer and inner endless woven plies ofrespective sets of weft yarns and main warp yarns, binder warp yarnsinterwoven with an interconnecting said outer and inner endless wovenplies, the warp yarns of each ply extending transversely across theendless belt fabric, the weft yarns in each ply extending lengthwisethereof and around the belt fabric in substantially endless form, all ofthe yarns being multifilament synthetic yarns, and each of the pliesbeing a mesh weave having interstices therethrough forming an open areaof at least about 9% per square inch of each ply with the interstices ofeach ply being substantially uniformly distributed throughout therespective ply for permitting liquid to drain through the Fourdrinierbelt fabric.
 8. A Fourdrinier fabric comprising at least two woven pliesof respective sets of weft yarns and warp yarns, binder yarns interwovenwith an interconnecting said two plies, and each of said plies being inthe form of a mesh weave having an open area of at least about 9% persquare inch thereof.